SPRINGFIELD - Jurors in the murder case against Juan Perez Friday watched a videotaped police interview with Perez the night he turned himself in to police after shooting Reynaldo Fuentes.

Perez, 28, of Holyoke, told police he came in, knowing the police were looking for him, "because I shot someone."

The very distraught looking Perez said Fuentes came at him and said he would shoot him, so he pulled a gun and shot Fuentes as Fuentes ran away.

Defense lawyer David M. Hodge told the Hampden Superior Court jurors at the start of the trial the fatal shooting of Fuentes by Perez was not murder.

"This was an act of self defense by a desperate individual on June 20, 2011," Hodge said.

Assistant District Attorney James M. Forsyth said Perez chased the 23-year-old Fuentes, who tripped and fell to the ground where Perez shot him.

Forsyth wrapped up the prosecution's case Friday afternoon, and Hodge called Christina Alvarez.

Alvarez is the mother of two of Perez' children, and had a relationship with Fuentes that she described as starting well and then quickly getting a dark side.

Alvarez said despite the split between Perez and herself about a year before Fuentes was shot, Perez saw the children all the time and was a very active father.

She said Fuentes was enraged when Perez came to pick up the kids. "He (Fuentes) would talk crazy to me. He'd be jealous," she said.

In addition to facing murder and gun charges from June 20, 2011, Perez is also charged with assault and battery with a dangerous weapon for stabbing Fuentes in the back of his arm May 25, 2011.

Jurors also watched a videotape of Perez being interviewed by Holyoke Police Detective James McGillicuddy after that incident.

In it, Perez tells McGillicuddy he was simply handing his children $5 each on a sidewalk when Fuentes came at him and punched him and he took out a knife and stabbed Fuentes in the arm in self defense. He said he had never carried a knife until Fuentes began threatening him.

Perez said Fuentes threatened to shoot him. McGillicuddy said Perez made it clear in that interview he was afraid of harm from Fuentes.

McGillicuddy and Holyoke detective Jennifer Sattler both testified Perez was cooperative, respectful and polite to them in two different police interviews - one after the stabbing and one after the fatal shooting.

McGillicuddy said when police got the stabbing call, Fuentes was very agitated but not cooperative. He said Fuentes said he got cut by falling and when showed Perez sitting in a police car, denied Perez did anything.

Alvarez told jurors what she saw on May 25, 2011. She said the children were excited to see Perez, and when Perez was giving them money, she saw Fuentes jump from the passenger seat of a car - clearly very agitated - and come at Perez and punch him on his temple.